Method for manufacturing a pvc film structure for packaging candy

ABSTRACT

The invention relates to a method for manufacturing a spool of PVC film, fine characteristics of which make it possible to manufacture a stiff PVC film that is transparent, colored or metallic, partially coated front and back with a thermosealable lacquer, having a specific chemical composition, which conforms to a defined shape, both in design and angles, characterized in that the enamel-type substance is continuously applied on one side of the longitudinal PVC film, such that the substance is applied to the peripheral portion of said side of the PVC film, the substance not being applied to the center portion, and at continuous application of the enamel substance on the other side of the same longitudinal PVC film, such that the substance is applied to the entire said other side of the PVC film, the film being printed with a design. The problems of jamming of the material are avoided, thus optimizing the packaging speed and substantially improving the look of the final packaged product.

PURPOSE OF THE INVENTION

The purpose of this Invention Patent application is to register aprocedure to manufacture a structure in a film to pack candies; thisfilm consists of remarkable innovations and advantages in comparisonwith the techniques used up to now.

Concretely, the invention suggests the development of a procedure tomanufacture a film reel which, due to its particular arrangement, allowsthe manufacturing of a transparent pigmented rigid film (which, in somecases, can be metallized); it is coated partially on both sides with aheat sealing resin of a specific chemical formulation and that isregistered according to a particular geometry defined according to thedesign an angles.

BACKGROUND OF THE INVENTION

Films used to pack or wrap products such as candies are well known inthe current state of the art.

The addition of certain coatings to the sides of those films is adecisive factor in the performance of the structure throughout theprocesses to pack products like square candies through folding.

This supposes that some blocking problems can occur in the materialsometimes.

The presentation of the final packed product can be affected because thefinal creases are sometimes poorly folded.

This invention contributes to solve this problem because it allows themanufacture of a suitable film used to wrap a certain food product andeliminates the material blockage problems; also, it improves thepresentation of the final packed product and increases thepacking/wrapping speed.

DESCRIPTION OF THE INVENTION

The present invention has been developed to provide a procedure tomanufacture a film used to wrap/pack candies; this packing procedure isdone on a film that unrolls from a reel and characterizes essentiallybecause it comprises the following steps once it unrolls from the reel:

-   -   A. The continuous application of a resin-type product on one        side of the film; the application is done on the peripheral        region of the film side so that the central region of the side        is not coated.    -   B. The continuous application of a resin-type product on the        other side of the same film; the application is done on the        entire surface of the film using a certain pattern.

Additionally, the product applied in the procedure to manufacture acandy wrapping film is a vinyl resin.

Preferably, the vinyl resin applied in the procedure to manufacture acandy package is a sealing resin.

Alternatively, in the procedure to manufacture said film, theapplication is done using photoengraving printer.

Besides, in the procedure to manufacture the film to wrap candies, atleast one of the sides of the film is color printed before theapplication of this resin-type product.

Thanks to this invention, a film is manufactured; said film is suitablefor the packing of food or human consumption products, namely, caramels;it avoids the blockage material problems and improves substantially thepresentation of the final packed product because it prevents the finalcreases to be poorly folded and increases the wrapping speed.

Other features and advantages of the procedure to manufacture the filmused to wrap candies are evident in the description of a preferredexecution which is illustrated as a non-limiting example in the drawingsattached herein which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1.—This is a schematic representation of a preferred execution ofthe procedure to manufacture a film used to wrap candies, the purpose ofthis invention.

FIGS. 2 and 3.—These are schematic views of some details of theapplication and the result of the preferred method for the procedure tomanufacture a film to wrap candies, the object of the present invention.

DESCRIPTION OF THE PREFERRED EXECUTION

As it is shown in FIG. 1, the procedure to manufacture the film to wrapcandies, adapted for its execution on a film (12) that unrolls from areel (11), after the unrolling 1 from the reel (11) comprises:

-   -   A. A continuous application 2 of a resin-type product on one        side of the film; the application (2) is done on the peripheral        region of the film side (12) so that the central region of the        side is not coated.    -   B. The continuous application 3 of a resin-type product on the        other side of the same film (12); the application is done to the        entire surface of the film (12) using a certain pattern.

As it is shown in FIG. 2, the first continuous application 2 is doneright after the film unrolls 1 from a reel (11).

FIG. 2 shows that the application 2 is done on the peripheral region ofthe film side (12) so that the central region of the side is not coated.

Next, FIG. 3 shows that a second continuous application 3 of aresin-type product is done on the other side of the same film (12); theapplication 3 is done to the entire surface of the film (12) using acertain pattern.

In some preferred alternative executions, at least one side of the film(12) is color printed before the application 2 and 3 of this resin-typeproduct.

In preference, the film (12) is a PVC polymer with a plasticizer-freeformulation that gives the film (12) the necessary rigidity to befolded. The substrate is generally transparent, but some applicationsmay require it to be pigmented (especially, in white) or have a metallicfinish, that is, with a superficial aluminum deposit that can be 0.0.3microns thick.

Once extruded, the film (12) is very stable and has the capacity toreceive both the color inks and the sealing resin coatings on itssurface.

In this preferred execution, the film (12) is a PVC film of K57Polyvinyl Chloride, a Carboxylate stabilizer, and the impact modifiermethacrylate butadiene styrene (MBS).

In this preferred execution—in which the substrate is PVC—the resin-typeproduct is a vinyl resin because it performs better given the coatingcomposition formulation. It must be complemented by an ester-typeorganic solvent and specific additives to achieve other properties suchas antistatic agents, carnauba-like sliding waxes, and antistatic agentsobtained from quaternary ammonium salts.

Concretely, the vinyl resin in this preferred execution is a sealingresin with a dispersion of copolymers of a vinyl resin in a mixture ofester-type organic solvents and a set of additives that improvesubstantially its performance in machinery. The sealing resin issupplied liquid to the printer; and in the printing process all thesolvent evaporates using large drying tunnels.

The main purpose of the sealing resin is to fuse on the surface of thefilm (12) once it achieves the adequate temperature through a contactclamp. These fusion allows the creation of a cohesive seal with itselfand adhesive seal with the substrate. This guarantees tightness andintegrity of the package with the product.

The formulation of the sealing resin is actually a dissolution of avinyl resin that attains 10% of solids in a solvent medium of ethylacetate and n-propyl acetate. The formula is complemented with a liquidantistatic agent of the quaternary ammonium salt type, a silicaantifoaming agent, and a carnauba-like natural wax to facilitatesliding.

The solid resin is dissolvent in a reactor with a cooling jacket; suchreactor has been previously supplied with the solvents and all theadditives. The result is a transparent varnish-type resin which fluidityfeatures allow it to be applied on the surface of the substrate, thusleaving the solid component on the substrate and permitting theevaporation of the solvent by means of passing from the liquid state tothe gaseous.

The main properties of the sealing resin are summarized in the followingtable and must be subject to strict control during the manufacturing andstorage process.

Property Detail Viscosity 19 seconds in Zahn Cup No. 2 Solids 10%Appearance Transparent Volatile [substances] 90% Starting temperature120° C.

In a preferred execution, applications 2 and 3 of the resin-type producton the film (12), such as the sealing resin, is done by a printer orlacquer using the rotogravure method.

Rotogravure presses have a unit to which an engraved cylinder isattached at certain ceil and depth pitches. This cell-like engravingholds the exact quantity of resin; and after a turn and the directcontact with the substrate in a continuous process, it is spread on thesurface; and the solvent evaporation process starts immediately after asa result of the temperature of the hot air tunnels.

In addition to controlling the conditions of the process and theapplication of the sealing resin, the successful performance of thestructure is based on the dimensions, spatial layout, geometry, andangles in which the resin is applied upon the film area.

This configuration allows each of the creases to ensure the product'stightness and seal required for its distribution and consumption whileit makes it easy to open. That is, it has a tight seal but can still beopened easily.

This product's specialization is the result of a thorough investigationof the seal's behavior until a fine adjustment was achieved to obtain adifferent result.

The geometry defined to apply the temperature sensitive resin isessential for the good performance of the structure. Other importantaspect that complements the necessary features of the structure is thedifference between the interior and exterior resins.

Ensuring an adequate coating of each of the film's (12) sides is asignificant contribution for the optimal performance of the packagestructure. One film (12) side receives the consecutive diamond-shapepattern (FIG. 3) in a machine-direction orientation and a point ofcontact in one of its vertices. On the other side of the film (12) theapplication 2 is done continuously in no particular design (FIG. 2).

The interior resin follows a continuous application pattern as it can beseen in FIG. 2 (shaded area), and it is aligned with the extrusiondirection of the film (12); it is spatially located toward the externaledges of the reel (11). These film edges will fold to form the sealingflaps of the product (cube).

The resin-free area in the center of the reel (11) (unshaded area ofFIG. 2) is an important area to hold the product that will be packed; asit is a food product it cannot be in touch with the coating.Additionally, due to friction coefficient conditions, it prevents thecandy to slide during the packing process.

The engraving with of the two continued resin bands has been calculatedparticularly for the length of the sealing flaps, e.g. 13 millimeters.The width of the reel (11) is, for example, 46 millimeters.

The exterior resin is the most important coating for the performance ofthe product. Unlike the interior resin, the continuous vertex-aligneddiamond-shape geometry covers the entire area of the reel (11) (FIG. 3).The colored area identifies the presence of resin while the unshadedarea is resin-free. This configuration ensures that the sealing strengthobtained reach a perfect level to guarantee the tightness and theproduct can be easily opened when consumed.

The design shows clearly two diamond rows (121) separated, for example,6 millimeters between edges, a 90° angle, and a wall thickness of 1millimeter. The diamond row is located symmetrically toward the edge ofthe reel and reinforces the sealing (FIG. 3).

The remaining rows form a grid (122) with a smaller contact area; theirdistance between vertices is, for example, 4.2 millimeters at a 74°angle, and a wall thickness of as much as 0.5 millimeters.

A commonly used interval of angles can range 45 to 90 degrees because itis the common interval to make the candy package creases. A 74°alternate angle is useful to fill in the free spaces left by the90-degree grid.

The total width of a packing machine feeding reel (11) (this machine isnot the purpose of this invention) is, for instance, 46 millimeters.

FIG. 3 shows detail of the geometrical layout; however, the resincoating is actually transparent so, it can be unnoticed at a glance.

With the procedure to manufacture the film used to wrap candies underthe present invention, one can manufacture a film suitable for thepacking of food or human consumption products such as candies; the filmeliminates the material blockage problems and improves substantially thepresentation of the final packed product because the creases areproperly folded; it also enhances the packing speed to a pace of 1,200candies per minute.

The final product resulting therefrom is a printed film (12) reel withtwo resins and the pattern mentioned.

This film has all the process conditions described above; and all thecontrol parameters that ensure its properties must be completely definedin the film.

The finished film containing these characteristics can be used to pack asquare caramel (in the shape of a cube) using a machine that integratesthe reel with the caramels; it uses folding devices and takes advantageof the heat transferred by conduction through some electric resistances.

The film can also be printed in 1-8 colors according to the graphicinformation and the product image supplied by the client.

Said film can be used in machines at different speeds; in general, ifaccompanies the in-line cutting process of the candy to be packed wherethe feeding, package folding, and sealing steps are executed. Thissealing is achieved using an electrical resistance with a temperaturecontrol that ensures a minimum variation of the value set in order toobtain complete tightness.

Details, shapes, dimensions, and other accessory elements, as well asthe materials used in the procedure to manufacture the film used to packcandies under this invention can be conveniently substituted by otherequivalent materials or accessory elements that do not differ from theessence of the invention or the field defined by the claims includedhereinafter.

1. Procedure to manufacture a film (12) used to pack candies,characterized because it comprises the following steps afterunrolling/unwinding (1) from the reel (11): A. A continuous application(2) of a sealing resin on one side of the film (12); the application isdone on the peripheral region of the film (12) side so that the centralregion of the side is not coated. B. The continuous application of aresin-type product on the other side of the same film; the applicationis done on the entire surface of the film using a certain pattern ofconsecutive diamonds in a machine-direction orientation and a point ofcontact in one of its vertices.
 2. The procedure to manufacture a filmused to pack candies according to claim 1 and characterized because theapplication (2,3) is done by a printer or lacquer using the rotogravuremethod.
 3. The procedure to manufacture a film used to pack candiesaccording to claim 1 and characterized because at least one of the film(12) sides is color printed before the application (2,3) of the sealingresin.
 4. A film to pack candies that characterizes because it isproduced following the manufacturing procedure described in claim 1; itcomprises a pair of longitudinal sealing resin bands (2), and thecentral region is resin-free. The other film side shows a longitudinalconsecutive diamond-shape pattern with a point of contact in one of itsvertices.
 5. A film to wrap/pack candies according to claim 4 andcharacterized because the diamond-shape pattern comprises two rows oflarger diamonds (121) that are located symmetrically toward the edge ofthe reel.
 6. A film to wrap candies according to claim 5 andcharacterized because the distance between the edges of the diamond rows(121) is 6 millimeters, the wall thickness of said diamonds is 1millimeter, and the angle α is between 45 and 90 degrees.
 7. A film towrap candies according to claim 6 characterized because angle α is 90°.8. A film to pack candies according to claim 5 and characterized becausethe remaining rows form a grid with a smaller contact area. The distancebetween vertices is 4.2 millimeters, the thickness, 0.5 millimeters, andangle β ranges 45-90 degrees.
 9. A film to pack candies according toclaim 8 and characterized because angle β is 74°.
 10. A film to wrapcandies according to claim 4 and characterized because it is a PVC film(12).
 11. A film to wrap candies according to claim 4 and characterizedbecause the sealing resin is produced from a resin, a solvent andselected additives that include antistatic agents, sliding waxes, andantifoaming agents.